Touch screens have become the main human-computer interaction means of personal mobile communication devices and integrated information terminals, e.g., a tablet computer, a smart phone and a super notebook computer, due to advantages of operability, visuality, flexibility and the like. The touch screens can be divided into four main types of a resistive touch screen, a capacitive touch screen, an infrared touch screen, a surface acoustic wave (SAW) touch screen and the like according to different touch principles, among which the capacitive touch screen has a multipoint touch function, short response time, a long service life and relatively high transmittance, and superior user experience; and meanwhile, along with gradual maturity of manufacturing processes, yield is obviously improved, the price of the capacitive screen is reduced increasingly, and currently, capacitive touch screens have become the main technology for touch interaction of small and medium-sized information terminals.
The capacitive touch screens suffer from the defect that it is vulnerable to the environment, and in the case where a user touches a capacitive touch screen when wearing gloves or touches it with a finger with water, or when the capacitive touch screen is used outdoors on a rainy day, a snowy day or the like, it is difficult for the capacitive touch screen to accurately capture the generated touch behavior. Meanwhile, the capacitive touch screen has a problem of causing a touch misoperation by relatively high sensitivity when the finger is suspended in the air above the touch screen. Moreover, the capacitive touch screen only senses a touch position on a plane (X-axis, Y-axis two-dimensional space) where a screen body is positioned, and it is difficult to support sensing of the touch parameters of a plane (Z axis) perpendicular to the screen body.